Philosophiae Doctor - PhD / The matter power spectrum is key to understanding the growth of large-scale structure in the Universe. Upcoming surveys of galaxies in the optical and HI will probe increasingly large scales, approaching and even exceeding the Hubble scale at the survey redshifts. On these cosmological scales, surveys can in principle provide the best constraints on dark energy (DE) and modified gravity models and will be able to test general relativity itself. However, in order to realise the potential of these surveys, we need to ensure that we are using a correct analysis, i.e. a general relativistic analysis, on cosmological scales. There are two fundamental issues underlying the general relativistic (GR) analysis. Firstly, we need to correctly identify the galaxy overdensity that is observed on the past light cone. Secondly, we need to account for all the distortions arising from observing on the past light cone, including redshift distortions (with all general relativistic effects included) and volume distortions. These general elativistic effects appear in the angular power spectra of matter in redshift space. We compute these quantities, taking into account all general relativistic large-scale effects, and including the important contributions from redshift space distortions and lensing convergence. This is done for self-consistent models of DE, known as ‘quintessence’, which have only been very recently treated in the GR approach. Particularly, we focus mainly on computing the predictions (i.e. the power spectra) that need to be confronted with future data. Hence we compute the GR angular power spectra, correcting the 3D Newtonian calculation for several quintessence models. We also compute the observed 3D power spectra for interacting DE (which until now have not previously been studied in the GR approach) – in which dark matter and DE exchange energy and momentum. Interaction in the dark sector can lead to large-scale deviations in the power spectrum, similar to GR effects or modified gravity. For the quintessence case, we found that the DE perturbations make only a small contribution on the largest scales, and a negligible contribution on smaller scales. Ironically, the DE perturbations remove the false boost of large-scale power that arises if we impose the (unphysical) assumption that the DE perturbations vanish. However, for the interacting DE (IDE) case, we found that if relativistic effects are ignored, i.e. if they are not subtracted in order to isolate the IDE effects, the imprint of IDE will be incorrectly identified – which could lead to a bias in constraints on IDE, on horizon scales. Moreover, we found that on super-Hubble scales, GR corrections in the observed galaxy power spectrum are able to distinguish a homogeneous DE (being one whose density perturbation in comoving gauge vanishes) from the concordance model (and from a clustering DE) – at low redshifts and for high magnification bias. Whereas the matter power spectrum is incapable of distinguishing a homogeneous DE from the concordance model. We also found that GR effects become enhanced with decreasing magnification bias, and with increasing redshift.

Bakgrund: Patienter som ventilatorvårdas på intensivvårdsavdelning behöver ofta någon form av lätt sömn (sedering) för att tolerera endotrachealtuben och ventilatorbehandling. De traditionella intravenösa läkemedel som ges har lång halveringstid och det är stor risk för kvardröjande effekter. Syfte: Denna pilotstudie syftar till att studera sederingsdjupet enligt MAAS hos de patienter som blivit sederade med inhalationsgas, kontrollera vakenhetsgraden enligt GCS hos dessa patienter efter avslutad sedering, samt beskriva vilka patientgrupperna är som fått inhalationssedering. Metod: Journalgranskning där resultatet har analyserats och kategoriserats, därefter har en sambandsanalys gjorts. Resultat: I resultatet identifierades 3 patientkategorier som fått isofluransedering: patienter med hotad luftväg som förväntats behöva kort sederingstid och snabb väckning, patienter som var svåra att sedera optimalt med intravenös metod samt patienter med organsvikt där risk för ackumulation och/ eller förlängd elimination av läkemedel förelåg. Något samband mellan MAAS 12 timmar före extubation och GCS- värde efter väckning hos de 14 patienter som ingick i studien har inte kunna styrkas. Konklusion: Inhalationssedering med isofluran förefaller vara en effektiv sederingsmetod när en lättstyrd sederingssituation med möjlighet till snabb väckning prioriteras, samt när man strävar efter att patienten ska uppnå 14-15 i GCS- värde så snart som möjligt efter väckning och extubation. / Background: Patients which are nursed by ventilator at the intensive care unit often need some form of sedative in order to tolerate an endotracheal tube and the ventilator treatment. The traditional intravenous drugs have a long half- life and potential risk for lingering effects. Aim: This pilot study aim to study the depth of sedation according to MAAS with the patients having been sedated with inhalation gas, check alertness according to GCS with these patients after completion of sedation, and describe which group of patients that have received inhalation treatment. Method: Journal Review where the result have been analysed and categorized then a link analysis has been made. Result: In the result three patient categories were identified which had received isoflurane sedation: patients with threatened airway and expected short time of sedation and fast wake- up, patients which were difficult to sedate optimally with intravenous method, and patients with organ failure where risk for accumulation and/ or  extended elimination of drugs were expected. Any relationship between MAAS 12 hour prior to extubation and GCS- score after awakening with the 14 patients included in the study have not been established. Conclusion: Sedation by isoflurane inhalation seems to be an effective sedation method when an easily controlled sedation situation with the possibility of a fast awakening are prioritized as well as when the strive is to achieve a GCS- score of 14-15 as soon as possible after awakening and extubation.

The near collapse of extension services in Limpopo Department of Agriculture (LDA) particularly evident in its failure to respond to the needs of the majority of small-scale farmers, presents a major problem from an agricultural and rural development point of view. This calls for an urgent and holistic intervention, in terms of an appropriate extension approach and policy, and prompted this research focusing on the search and development of an appropriate extension approach and corresponding policy for the LDA. For such a policy to be acceptable at the operational level, the emphasis has been on maximum involvement and participation of extension personnel. A total of 324 front line extension workers and managers, representing a 40 percent sample, were involved in group interviews in which their opinions were captured in semi structured questionnaires after exposure to nominal group and Delphi techniques. From the research no particular extension model emerged, but rather a series of principles, which, depending on a specific situation, could be combined and implemented to different degrees. Respondents’ opinions regarding these principles and their dimensions formed the basis of recommendations for a policy framework. These recommendations, based on informed opinions of respondents, include a need-based but priority focused approach relying on a compromise between felt and unfelt needs rather than only the felt needs of community members. For the implementation of participatory development that will ultimately allow for community empowerment and ownership, institutional linkage structures are recommended that provide for effective coordination and integrated operational activities, and having primarily a commodity focus. A strong knowledge support system, having as target audience front-line extension workers rather than farmers, is important in view of the large percentage of under-qualified extension staff. A national (or provincial) monitoring and evaluation programme is seen as an issue of high priority, with a stronger emphasis on monitoring using behaviour determinants (forces of change) as main criteria, but covering also the full range of in- and output criteria in the evaluation process, which if used together with a purposeful and programmed approach, can go a long way in improving current and future extension in Limpopo. / Thesis (PhD)--University of Pretoria, 2009. / Agricultural Economics, Extension and Rural Development / unrestricted

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This dissertation examines the impact of academic information on the capital markets. A test of market learning from academic information is performed by examining the impact of published research about the size anomaly on the underlying asset pricing process. A theoretical framework to examine the effect of events that affect the equilibrium pricing process is first developed in a simple economy with one single risky asset. A learning model based on Bayesian updating is proposed and its empirical implications are derived. The model predicts a change in the asset prices in the case of market learning. The predictions about the learning path depend on the assumed information structure. The key hypotheses are motivated through an illustrative case in a multi-asset economy where there is more information available concerning large firms than about small firms. The econometric model of switching regimes is used to analyze the hypothesized structural change in the mean returns associated with the size variable. We postulate two regimes, one prior to and another after the incorporation of research information on the size anomaly. We find evidence of a switch in regimes with estimated mean switch located in 1983. The estimated average size premium has declined from approximately 13.6% per annum in the first regime to about -2.8% per annum in the second regime. More importantly, the switch in 1983 is not explained by any of the hypothesized economic factors that explain a large part of the stochastic variation in the size effect in the periods prior to 1983. We also find evidence of a switch in regimes when the seasonal January size effect is excluded. The evidence also suggests an increase in the trading volume associated with the information arrival. Our evidence strongly suggests that the market has undergone a change in its underlying equilibrium pricing process after the discovery of the size anomaly. The evidence supports the hypothesis that academic research relating to the size anomaly has provided useful information to the investors and the market has learnt from this information. / Business, Sauder School of / Graduate

The WISC-R (Wechsler, 1974) was administered to 29 good spellers and 31 poor spellers in grade six. The obtained scaled scores were recategorized in the manner suggested by Bannatyne (1974) into Spatial (Block Design, Object Assembly, and Picture Completion), Conceptual (Vocabulary, Similarities, and Comprehension), and Sequential (Digit Span, Coding, and Arithmetic) categories. The poor spellers were highest (mean score) in the Spatial category, intermediate in the Conceptual category, and lowest in the Sequential category. The good spellers were highest in the Conceptual category, intermediate in the Sequential category and lowest in the Spatial category. These results are similar to those obtained in Bannatyne's 1971 study of genetic dyslexic children, and other studies reported in the literature for disabled and retarded readers. The implications of these findings are briefly discussed. / Education, Faculty of / Educational and Counselling Psychology, and Special Education (ECPS), Department of / Graduate

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Reheating furnace is a furnace that using fuel combustion energy to heat steel products before hot rolling. Materials need to reach the temperature around 1400K uniformly after heating in reheating furnaces. Steel oxidizes during the reheating process. Oxidize scale layer on the surface will changed the heat transfer properties of surface and increase the inner stress of material, reducing the quality of the steel. In this study, a model of scale formation under reheating furnace working condition is developed. The model can be coupled into computational fluid dynamics (CFD). The commercial software, ANSYS FLUENT®, was utilized to give a prediction of furnace atmosphere and calculate the formed scale. A calculator is also developed to predict the scale formation of a single point during the reheating process using measurable flow field data. Furthermore, a series of parametric studies has been investigated to study the influence of operating conditions.

Thesis (M.Sc. Agriculture (Agricultural Economics)) -- University of Limpopo, 2021 / Groundnut is one of the most important agricultural crops in South Africa. It provides economic and health benefits to the society. Its production, processing and marketing provides employment to several individuals in South Africa. The objectives of the study were: to identify and describe the socio-economic characteristics of small-scale groundnut farmers, analyse the determinants of commercialization and the factors influencing the choice of market outlet in Capricorn district. The study was conducted in three villages (Ga-Maja, Ga-Mphahlele and Moletjie). Purposive sampling technique was used to select 110 small-scale groundnut farmers. Semi-structured questionnaires were used to collect data from the small-scale groundnut farmers through face-to-face interviews. The data was analysed using the descriptive statistic, Logistic Regression and Multinomial Logit model. SPSS and STATA software were used to process the data. The results indicated that quantity of groundnut produced, occupation, marital status, household size, land size, vehicle ownership, access to credit and extension contact significantly influenced the commercialization and the choice of market outlet of the small-scale groundnut farmers in the study area. The study recommends that the government in collaboration with universities and agricultural colleges as well as the private sector initiate an extension programme that will focus on small-scale farmers, rather than on emerging and commercial farmers only. This will enable the small-scale famers to get access to information on the market, production, price and other agricultural related activities. It further recommends that the Department of Agriculture visit areas where farmers produce the same type of crops and offer them incentives to pool their resources and market their produce collectively. This will improve the bargaining position of the small-scale farmers as well as the means of lowering transaction costs. / National Research Foundation (NRF)

This international workshop entitled “How to integrate geochemistry at affordable costs into reac-tive transport for large-scale systems” was organized by the Institute of Resource Ecology of the Helmholtz-Zentrum Dresden Rossendorf in Feb-ruary 2020. A mechanistic understanding and building on that an appropriate modelling of geochemical processes is essential for reliably predicting contaminant transport in groundwater systems, but also in many other cases where migration of hazardous substances is expected and consequently has to be assessed and limited. In case of already present contaminations, such modelling may help to quantify the threads and to support the development and application of suitable remediation measures. Typical application areas are nuclear waste disposal, environmental remediation, mining and milling, carbon capture & storage, or geothermal energy production. Experts from these fields were brought together to discuss large-scale reactive transport modelling (RTM) because the scales covered by such pre-dictions may reach up to one million year and dozens of kilometers. Full-fledged incorporation of geochemical processes, e.g. sorption, precipitation, or redox reactions (to name just a few important basic processes) will thus create inacceptable long computing times. As an effective way to integrate geochemistry at affordable costs into RTM different geochemical concepts (e.g. multidimensional look-up tables, surrogate functions, machine learning, utilization of uncertainty and sensitivity analysis etc.) exist and were extensively discussed throughout the workshop. During the 3-day program of the workshop keynote and regular lectures from experts in the field, a poster session, and a radio lab tour had been offered. In total, 40 scientists from 28 re-search institutes and 8 countries participated.